DDM Trilogy with the "Energy-peak" Method: MeV, GeV, and TeV

We study a possible way to interpret (continuous) cosmic gamma-ray excesses in the context of the dynamical dark matter (DDM) framework, in particular, the scenarios in which the signal photons come from the annihilation/decay of constituent DM particles. While the masses of constituent DM particles in typical DDM scenarios are discretized, relevant photon spectra could appear as continuum bumps with the mass gap among them being much smaller than the energy resolution of the detector. To prove the principle, we employ dark matter indirect detection signatures in MeV-range (future data) and GeV-range (the Galactic Center GeV excess) cosmic gamma-ray observations. We also discuss a potential connection of the cosmic-ray phenomena with a TeV-scale resonance particle which would emerge in collider experiments such as the LHC.